Portion of a burner assembly



FIG. 1 is a front perspective view of a portion of a burner assembly showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a side view thereof;

FIG. 5 is an alternate side view thereof; and,

FIG. 6 is a top view thereof.

The unshown bottom surface of the burner assembly forms no part of the claimed design. 

The ornamental design for a portion of a burner assembly, as shown and described. 